Plant Cell Features

All plant cells are characterized by several common features, such as chloroplasts, a cell wall, and a large vacuole. These features also differentiate plant cells from animal cells. In addition, there is a number of specialized types of plant cells that are found only in vascular plants. These include parenchyma cells, collenchyma cells, and sclerenchyma cells.

1. Parenchyma cells

The term parenchyma is derived from the Greek word para, which means “beside”, and en + chein, meaning “to pour in”. Parenchyma cells are the biochemistry machines of the plant. They are usually described as the typical plant cell, because they are not very specialized. These cells are commonly found in leaves, roots, and stems, usually having a spherical shape with only primary cell walls and highly functional cytoplasm.

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Parenchyma cells play an important role in food storage, photosynthesis, and aerobic respiration, meaning that they synthesize and store organic products in the plant and are the place where most of the plant’s metabolism takes place. These cells are alive at maturity and are responsible for a wide range of biochemical processes. Most parenchyma cells have the ability to differentiate into other cell types under special conditions

2. Collenchyma cells

The term collenchyma is derived from the Greek word kola, meaning “glue”. Collenchyma cells have a support function in plants, particularly in young plants. They help to support plants while not restraining growth due to their lack of secondary walls and the absence of a hardening agent in their primary walls. This means that their main function is to provide support for parts of the plant that are still growing, such as the stem.

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Collenchyma cells form strands or continuous cylinders just below the surfaces of stems or leaf stalks. They are similar to parenchyma cells in the sense that they are alive at maturity. To better understand what collenchyma cells do, imagine a stretchable support, without elastic snap-back.

3. Sclerenchyma cells

The term sclerenchyma is derived from the Greek word skleros, which means “hard”. Sclerenchyma cells are the ones providing rigid support for the plant, because they have a hardening agent and are much more rigid. These cells develop an extensive secondary wall that is invested with lignin (the main chemical component of wood), making it extremely hard. Besides support, sclerenchyma cells have other functions, which include discouraging herbivory, and conduction.

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There are two types of sclerenchyma cells – fiber and sclereid. Fiber cells are long, slender cells that usually form strands or bundles. Sclereid, also known as stone cells, occur singly or in groups and have various forms. Most sclerenchyma cells are dead cells at maturity. Sclerenchyma cells cannot survive for long because lignin also makes the wall waterproof, therefore making it impossible for the cells to exchange materials long enough for active metabolism.

These are the main and most important types of specialized plant cells. Other specialized plant cell types include xylem, phloem, and epidermis cells.

Plants have a wide variety of mechanical properties that may inspire engineers to design new materials.
Lorna Gibson, the Matoula S. Salapatas Professor of Materials Science and Engineering at MIT says:
‘If you look at engineering materials, we have lots of different types, thousands of materials that have more or less the same range of properties as plants. But here the plants are, doing it arranging just four basic constituents. So maybe there’s something you can learn about the design of engineered materials.”

Engineers claim that some plants such as bamboo, maples, palm trees or potatoes inspire them, being a great example of precise engineering on a microscopic scale. The way their cell walls are arranged and what they’re made of, some plants may be sturdy as an oak, while others as flimsy as a reed.

To Lorna Gobson, many cell walls’ components resemble certain manmade materials such as cellulose, hemicellulose, which can be strong and stiff as manufactured polymers. Additionally, cells in woods are aligned similarly to engineering honeycombs, while polyhedral cell configurations found in apples look like industrial foams.

Gibson researched plants’ natural mechanics and focused on three main plant materials: oak, cedar and woods, parenchyma cells found in root vegetables and fruits and coconut trees. She and other scientists studies these plants and their cells and analyzed two main mechanical properties in each plant: strength and stiffness.

Plants are multicellular, eukaryotes organisms. They have membrane-bound organelles. A plant cell has a rigid cell wall, a central vacuole, plasmodesmata and plastids, which make it unique among all other type of eukaryotes cells. Plant cells sustain the photosynthesis process, during which oxygen is produced.

Plant cells are formed by different parts. All of them play an important role in the proper function of the cell.

1. Cell membrane

The cell membrane allows waste material to exit the cell. The membrane surrounds the cytoplasm of the cell. It actually forms a barrier between the inside of the cell and the outside area. The cell membrane regulates the movement of materials into and out of the cell. Having under consideration its function, the cell membrane is believed to be in a way similar to the skin.

2. Cell wall

The cell wall surrounds the cell. This is a rigid layer placed externally to the cell membrane. It offers structural support and protection to the entire cell. The cell wall also controls the amount of water that enters the cell. It allows the circulation of minerals and nutrients. The cell wall has the ability to sense the presence of pathogenic microbes, as well, being able to control the development of tissues within the cell.

3. Plasmodesmata

Plasmodesmata are microscopic channels of plants traveling the cell walls. It enables communication within the cell.

4. Tonoplast

The tonoplast surrounds a vacuole. Vacuoles are found in the cytoplasm, being membrane-bound compartments with storage functions.

5. Plastids

Plastids are some of the most important parts of the plant cell. They are responsible with photosynthesis, storage and synthesis.

6. Golgi Complex

Golgi complex is an organelle found in plant cells. It processes macromolecules, including proteins and lipids.

7. Chloroplast, Leucoplast, Chromoplast

Chloroplasts are organelles that conduct photosynthesis. They absorb light. Leucoplasts are plastids that are non-pigmented. Chromoplasts are plastids with role in pigment synthesis and storage.

8. Ribosome, Lysosome

Ribosomes are complexes of RNA and protein. Lysosomes are organelles which contain digestive enzymes.

9. Mitochondrion, Microtubule, Microfilament, Microbody

Mitochondrion is a membrane-enclosed organelle. Microtubules are components of the cytoskeleton. Microfilaments are the smallest filaments of the cytoskeleton. Microbodies are organelles of a globular shape.

10. Cytoplasm, Nucleus, Nuclear envelope

The cytoplasm is a semi-transparent fluid which fills cells. The nucleus contains the cell’s genetic material. The nuclear envelope is formed by two cellular membranes.

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Besides the aforementioned plant cell parts, DNA, chromatin and RNA should also be presented. DNA is the nucleic acid that contains genetic information, chromatin is a complex of DNA and protein, while RNA has an important role in translating genetic information from DNA to proteins.

In order to properly understand the functionality and the features of the plants, we have to look inside these for answers. That is the main reason why biology classes focus on the presentation of the internal mechanisms of plants in the first place and then move on to larger views. To start with the minimal element of the plant, we have to consider the plant cell. Here is a video that illustrates a tour through the plant cell, from which you can understand its structure and its functionality:

plant cells and animal cells are somewhat the same, but there are differences between them that set them apart;

the cell wall is the first stratum of the cell, which includes and protects all its other elements, and is made from cellulose fibers;

the central vacuole regulates the composition of the cell plasm, creates internal pressure and stores different compounds;

the chloroplasts are the ones in which the photosyntheses process takes place, for the creation of food for the plant;

the mitochondria is the one that breaks sugar molecules and converts them.

If you are looking for more extensive information about the plant cells, that will reveal all there is to know about these, from their origins and evolution, to compositions, classifications and functions, here is a crash course video, which will surely help you understand more and which is presented in a way that will catch all your attention:

Cells are the fundamental units of life. Without them, plants, animals and human beings would not exist today. Whether they be unicellular or multicellular life forms, all living organisms are composed of and depend on cells to function properly. Think of it this way: without plants, animals would not have anything to eat and humans would not be able to breathe. In the whole biotope there are not two cells alike. Every cell has a specific role and functions according to certain parameters.

There are two main types of cells:

1. Prokaryotic cells. This type of cell lacks a cell nucleus or any other membrane bound organelles, and live in almost all the environments of the earth.

2. Eukaryotes contain complex structures enclosed within membranes. Most of the eukaryote cells contain DNA, chloroplasts and the Golgi apparatus. This type of cell can be found in complex organisms, such as animals, plants and fungi.

Comparison of Prokaryote and Eukaryote Cells

The Role of Each Cell in Plants

The plant cell provides an excellent starting point for understanding how this type of cell functions and the role it has in a living organism. As a plant grows and matures, each cell becomes specialised. There are a number of important specialised types of plant cells that function on a different level. Some of the most important cells in a plant are:

Parenchyma Cells. These cells synthesise and store organic products in the plant. These cells help the plant to go through the process of metabolism.

Collenchyma Cells. These cells support the plant during its growth stage. They are important since they help the plant develop even it does not have the hardening agent in their primary walls.

Sclerenchyma Cells. These are the cells that help the plant to harden its walls and grow taller and stronger.

Water Conducting Cells. They have a support function in plants and represent the mechanism that helps water flow in the plant, in order to provide the necessary nutrients.

Sieve Tube Members are the ones that conduct important nutrients, such as sugar, all throughout the plant.

Metabolism of Plant Cells

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In order to stay alive people must provide their cells with the proper fuel – AIR. More specifically oxygen. This process has its roots in special plant cells called photosynthetic cells. These cells are found in green plants, phytoplankton and cyanobacteria. During the process of photosynthesis, cells use carbon dioxide and energy from the Sun to make sugar molecules and oxygen. These particular cells contain a special pigment that absorbs light energy. In the presence of carbon dioxide, these cells are able to convert solar energy into energy-rich organic molecules, such as glucose.